Nihon Kohden Corporation (日本光電工業株式会社) is a Tokyo-based leading manufacturer, developer and distributor of medical electronic equipment, which include EEGs, EMG measuring systems, ECGs, patient monitors, Invasive and Non-Invasive Ventilators, Defibrillators, AEDs and clinical information systems,[2] with subsidiaries in the U.S., Europe and Asia. The company's products are now used in more than 120 countries, and it is the largest supplier of EEG products worldwide.[3]
In 1972, Takuo Aoyagi, a researcher at the company, invented and patented the basic principles of pulse oximetry.[4] Two years later he developed the world's first pulse oximeter, the OLV-5100, which has helped improve patient safety during anaesthesia.[5]